Electromagnetic devices, such as motors, sensors, generators, and actuators, commonly include spoked stator cores supporting a number of electromagnetic coils. During operation of the electromagnetic device, the electromagnetic coils magnetically interact with a rotor to provide the desired transducer functionality, such as converting electrical signals to rotor rotation, converting rotor rotation to electrical signals, or converting rotor rotation to power generation. The electromagnetic coils are wound around or inserted over the spokes or posts of the stator core, which is at least partially composed of a magnetically-permeable alloy, such an electrical steel. Cost savings can be realized by producing the stator core as a monolithic structure composed entirely of the magnetically-permeable alloy. Alternatively, the stator core can be produced from laminated stack of magnetically-permeable plates or “laminations,” which are separated by intervening dielectric layers (referred to herein as “interlaminate dielectric layers”). While more costly than solid stator cores, laminated stator cores can significantly reduce eddy current loses and, in turn, enhance the efficiency and power density of the electromagnetic device into which the stator core is integrated. As conventionally produced, however, laminated stator cores are generally unsuitable for usage in high temperature applications, such as applications characterized by operating temperatures exceeding about 260 degrees Celsius (° C.) or about 500 degrees Fahrenheit (° F.).
Any one of a number of factors can contribute to the temperature limitations of conventional laminated stator cores. In many cases, laminated stator core temperature limitations are due to the presence of organic dielectric materials within the stator core. As do organic materials, generally, such organic dielectric materials tend to breakdown and decompose at elevated temperatures exceeding the aforementioned threshold. Other factors that can limit the thermal tolerances of laminated stator cores include degradation of the electrically-insulative properties of the interlaminate dielectric due to unfavorable interactions with the laminate alloy under high temperature operating conditions (e.g., mass migration of metal ions from the laminate into the dielectric) and/or the rapid oxidation of the laminates when exposed to air under high temperature conditions. In the majority of applications, such temperature limitations are immaterial as the laminated stator cores are not exposure to such highly elevated operating temperatures. However, in applications wherein the stator cores are subject to such temperatures, the thermal capabilities of conventional laminated stator cores can be undesirably limiting. Such applications can include, but are not limited to, utilization of the laminated stator cores within electromagnetic devices, such as motors, sensors, actuators, generators, or magnetic bearings, deployed within the hot section of a gas turbine engine.
There thus exists an ongoing demand for the provision of laminated stator cores capable of prolonged and reliable operation in highly elevated temperature environments, such as environments characterized by temperatures exceeding about 260° C. (˜500° F.) and, possibly, approaching or exceeding about 500° C. (˜930° F.). It is also desirable to provide embodiments of a method for manufacturing such high temperature laminated stator cores. Other desirable features and characteristics of the present invention will become apparent from the subsequent Detailed Description and the appended Claims, taken in conjunction with the accompanying Drawings and the foregoing Background.